Can a bad heater core make a car run hot?

Yes, a bad heater core can cause a car to run hot. If the heater core is clogged or leaking, it can disrupt the flow of coolant through the engine, leading to overheating. Additionally, if the heater core is leaking, it can result in a loss of coolant, further exacerbating the overheating issue. Regular maintenance and inspection can help prevent these problems.